Refrigerating apparatus



y 4 1938. D F. Mmmmm ET AL 2,118,636

REFRIGERATING APPARATUS Filed March 31, 1936 2 Sheets-Sheet 1 MB I ATTOR Yr y 1933- D. F. ALEXANDER AL 2,118,636

REFRIGERATING APPARATUS Patented May 24, 1933 PATENT oFF cE BEFRIGERATIN G APPARATUS 4 Donald Alexander and George C. Pearce, Dayton, Ohio, assignors to General Motors Corporation, Dayton, Ohio, a corporation of Delaware Application March 31,

' 10 Claims.

This invention relates to refrigerating apparatus.

An object of this invention is to provide a simplified form of control for air conditioning apparatus in which, at times, the power for the air conditioning apparatus is derived from a source of limited capacity.

Another object of this invention is to provide an improved control for air conditioning apparatus on a railway train, or the like, in which a source of energy of limited capacity is provided.

" and in which a plurality of compressing units are operated from this source, the control being such that the number of compressing units which may start simultaneously is limited, thus preventing the overloading of the source of power.

Further objects and advantages of the present invention will be apparent from the following description, reference being had .to theaccompanying drawings,.wherein a preferred form of the present invention is clearly shown.

In the drawings: 1

Fig. l is a diagrammatic representation of a railway train to which this invention is applicablc;

Fig. 2 is a diagrammatic representation of the wiring arrangement which is used to connect the various cars 'of the train; and

Fig. 3 is a diagrammatic representation of a slightly modified form of the invention.

This invention is applicable to a railway train, although it is to be understood that many of the features of this invention are applicable to devices or locations other than railway trains. In the railway train shown in Fig. 1, a source .of power may take the form of a generator 10 driven by an internal combustion engine ll. While only one generator and internal combus tion engine have been shown, it is within the purview of this invention that the source of power may include a plurality of generators and internal combustion engines. The power means may be mounted on the car l2. This car and/or other cars l3 and I4 may be provided with individual air conditioning systems which. are to derive their power mainly from the generator system l0 through the leads Ilia which extend throughout the train with suitable connectorsbetween cars. If desired, as will be more fully explained, arrangements are provided so that power may lie derived from the station or standby source will e the train is stationary.

Any suitable type of individual-air conditioning system maybe used. Thus, as shown in car l3 and as maybe also used on other cars, air for 1936, Serial No. 71,868

the space to be conditioned is delivered by a blower l5 driven by a motor "5.. This air may come from the space which is being conditioned or from the outside or both. This air is caused to flow over cooling surfaces or evaporator l1 and over heating means or coils l8 and is discharged through the grille l9 into the space '20. The refrigerating system for cooling the air during warin weather, may include, in addition to the evaporator l'l, a.condensing unit having a compressor 2 I, condenser 22, liquid receiver 23, liquid line 24 and vapor line 25. The compressor II is driven by a motor 26. The condenser fan 21 may be driven either from the motor 28, or, as shown, may be driven by an additional motor 28. The evaporator l'l may be-of the usual finned coil variety and may include an automatic expansion valve 29 which automatically opens when the pressure in the evaporator is reduced rbelow a predetermined limit, and the valve is also controlled by a thermostatic bulb ill which automatically throttles the valve when the refrigerant effect extends to the outlet of the evaporator. The heating means may include a' finned coil which is supplied with steam by the pipe 3| under the control of solenoid valve 32, while the condensate from the coil is discharged through the pipe 33 either through a trap to the outside of the car or is returned to the .boiler as desired.

Suitable automatic control instruments are placed in a position to be affected by the condi tion of the air in the compartment 20. Thus, they may be placed in the compartment itself, or in an air stream which receives air from the compartment, such as the stream which returns to the blower IS. The instruments may include various air condition stats, such as a humidistat 40, a thermostat H which opens at a certain warm temperature, a second thermostat 42 which closes at a certain cool temperature, and a third thermostat 43 which controls the refrigerating system and which closes at a definite warm tem perature. While specific thermostats and humidistatshaVe been disclosed, it is to be understood-that these may be replaced or used interchangeably, so lohg as they are made responsive to the desired air condition.

The generating system, which may include one or more generators I0, is provided with an automatic switch 44 which automatically closes whennormal or suflicient power is being generated by the generating system. When the switch 44 closes, the automatic controls for the refrigerating system are placed in control. A source of low voltage current, such as a battery 45 is charged 51 the contacts 62, 65, 66, etc.

from any suitable generator, and master leads from the battery 45 may extend through the train and include the negative lead 46, positive lead 41 and the power control lead 48. While a D. C. battery low voltage system has been shown for operation of the controls, it is to be understood that an A. C. control current may be used, in which case 45 may be a low voltage A. C. generator. A program control 49 is placed on one of the cars and so operates that only one compressor (or one group of compressors) can start at one time, as will be more fully hereinafter described. The arrangement is such that only one control wire 60 is required for the car 13, and only one additional wire- (5|, 52', etc.) for each additional car or compressor unit is required. All of the above wires, where indicated, extend from car to car with suitable connectors between cars.

The refrigerating system control for the air conditioning system is as follows. When refrigeration is required, the manual switch 53 is closed and this starts the blower motor I6 in operation. At the same time, the relay solenoid 54 is energized and this closes the relay contacts 55 and 56. This arrangement insures that the refrigerating system cannot be started unless the air blower I5 is started. If cooling is required, because of high temperature in the compartment 20,

.the thermostat 43 closes. The switch 56 is normally in its upper position (when the-system is not connected to standby power), and, therefore,

current tends to flow from the positive battery wire 48 (if the generator control 44 permits) through the starter solenoid 51, switch 56, overload devices 58 and 59, refrigerant high pressure and low pressure control 60, thermostat 43, and contacts 55; but is arrested at the point 6! until such time as the program control 49 permits current to flow through the corresp nding single wire 50, contacts 62 and lead 63 to negative lead 46. rotatable shaft 64 which progressively closes the contacts 62, 65 and 66, thus preventing the starting of more than the desired number of compressors at one time. It is therefore necessary, before the compressor 2i can start, for the contacts 62 to be already co-incidentally closed, or else to have the program starting device operate until the contacts 62 are closed.

The program starting device 49 operates as follows. When the line or connection from lead 48, solenoid 5], switch 56, contacts 58, 56, 66, thermostat 43, contact 55, point 6| and lead 50' is completely closed, (and assuming the contacts 62 are open), current flows through the solenoid 61 and lead 63 to lead 46, thus causing solenoid 61 to close the contacts 68. This permits current to flow from the positive side 41 of the battery through the program motor 69 to the negative side 46. The motor 69 drives the shaft 64 through the gear 16, thus progressively closing When the contacts 62 are closed by the rotation of shaft 64, the solenoid 61 is shunted, and if similar solenoids H and 12 are not energized, then the motor 69 is deenergized and coasts to a stop. During the time that contacts 62 are closed, current can flow through the line which incudes the solenoid 51, switch 56, etc., and can now flow through the lead 56 and contacts 62 to the leads 63 and 46, thus completing the circuit. When this occurs the solenoid 51 closes the contacts 13 and acts as a holding coil to maintain the operation of the refrigerating system even after the contacts 62 are opened and as long as the thermostat 43 re- The program device 49 includes a mains closed. When the foregoing circuit is completed, the solenoid 51 closes the motor starter contacts 14 and thus starts the motor 26 which drives the compressor 2|. At the same time the condenser fan motor 28 is caused to operate. This operation of the condensing unit continues as long as the thermostat 43 remains closed and as long as the overload devices 58, 59 and the high pressure and low pressure refrigerant controls 66 remain closed. When thermostat 43 opens, because the car has been cooled sufficiently, or any other control opens, the refrigerating system is stopped.

It is to be seen that an undesirable number of compressor motors cannot start simultaneously because the cranks l5, l6 and ll of the program device 49 only close the contacts 62, B5 and 66 in sequence and no two such contacts are closed at the same time.

The compressor 2i maybe connected to a high pressure bellows Ma and a low pressure bellows 2) which are linked to the contacts 60 so that these contacts are opened whenever the discharge pressure rises above a predetermined limit or when the suction pressure falls below a predetermined limit. The contacts 58 and 59 are opened by the overload devices 58a and 59a respectively which are in series with the motors 26 and 28.

The manual switch am is placed between point 6| and the lead 46. This switch Glais normally open, and can be manually closed whenever it is desired to shunt out the program starting device.

The refrigerating system for the car it (and for the other cars) may be operated from a standby source of electricity at a station or the like. In this case the standby plug illl isinserted in the receptacle ill at the station, which plug is connected by the power lines 82 with the station supply of current. The plug 66 is also provided with a jumper 83 which causes low voltage current to flow through the solenoid 34 when the plug is placed in receptacle 88. When the solenoid 64 is thus energized the switch 56 swings to the lower contact 56, thus placing the thermostat 43 in control of the standby current. if the thermostat 43 is closed, current can now flow through the line 85, starter solenoid 86, contacts 8'! and 56', switch 56, contacts 58, 59, 6E], thermostat 43, contacts 55 to the point 6 I. by source of current is sufllciently powerful to start all of the refrigerating systems at the same time, the program starting device 46 may he shunted out of the control system (although it is to be understood that it be allowed to remain in control if the standby current requires sequential starting). In order to shunt the program starter, contacts 88 are provided which are closed whenever suitable standby current is available. These contacts shunt the program starter by virtue of the lines 89 and 96 and may be made to close whenever the standby receptacle is plugged in. Vl hen the solenoid 86 is energized, the motor starter contacts iii are closed and stand-by current is delivered to the motors 2G and 26 under the control of thermostat 43.

The box 90a is a phase rotation control of such a character that the contacts 92, 8? and 88 are If the standanaose contact lllljit being understood that switch I00 is placed inan open position or in its lower position when refrigeration is desired. When switch Hill is in itsupper position, current from the lead 41 can then flow through the solenoid valve 3!, switch I00, thermostat 42, contacts 56 and lead 46 whenever the temperature is sufliciently low to close thermostat 42. This causes steam to flow into coil i8 and heat the car. It is, however, necessary always first to close manually the switch 53, thus energizing relay solenoid 54 and starting blower l5 before the thermostat 42 can take control of the heating system.

It may be desirable to operate the heating coilat certain times when the refrigerating system is also operating. This occurs when the temperature is fairly low and there is a large amount of humidity in the air. Under such conditions it is desirable to cool the air by evaporator I! to dehumidify the air and then to reheat the air to avoid too low a temperature. In order to accomplish this, the switch "I0 is placed on con tact I02. The humidistat 40 closes when the relative humidity is high and the thermostat 4i closes only at relatively cool temperatures, being opened at high temperatures. On a cool damp day when dehumidiflcation and reheat are required, the humidistat 40 and thermostat 4! close. This causes current to flow through the solenoid valve 32 and supplies steam to the heating coil at the same time that the refrigerating system can operate. The thermostats 4| and 43 may be so calibrated that thermostat 43 starts the refrigerating system whenever required under normal relative humidity conditions. On extremely damp and cool days, controls 40 and 4| start the heating coil, and if the temperature then rises to an uncomfortable degree, thermostat 43 starts the refrigerating system. If the temperature should rise to such an extent that the refrigerating system is likely to be taxed to or beyond its limit, the thermostat 4| opens and thus prevents the heating coil from operating even though the relative humidity is very high.

It is to be understood that the humidistat 40 and.

thermostat 4| may, if desired, be placed outside of the car, or in the fresh air inlet to the blower I! so as to' be responsive to outside air condi- ,tions.

Under certain conditions, it may be permis-' sible to allow the program starting mechanism to run all of the time that refrigeration is likely to be required. This may be done when the battery power is ample and is not likely to be deplated by the program control motor. Such an the motor 69a and causes it to run continuously arrangement is shown in Fig. 3. In this modiiie cation the program start control 48a may be substituted in the wiring diagram of Fig. 2. The switch H0 may be manually closed whenever refrigeration is likely to be required. This starts as long as refrigeration is likely to be required. The motor 69a drives shaft 64a. through gears 10a and continuously closes the contacts 62a,

65a and 66a in sequence. Whenever a thermoe stat on one of the cars closes and attempts to start its corresponding compressor, such starting operation is momentarily delayed until its mediate position on the train. To indicate this,

the wires Ill, 2, H3, H4, H5 have been shown as branches which may extend to the front of car l2 in addition to, or in lieu of, those extending to the rear. Thus, lines I, H2,'|l3 and H5 may extend to the front of car I! in. addition to those extending to the rear, while wires 4 indicate that program control wires may extend to the front of the train in addition to those extending to the rear.

. This invention is applicable 'to places other than railway cars. It is applicable for the purpose of eliminating voltage fluctuations on lights, blower motors, etc., due to sudden application of heayy starting current loads.

The solenoids 51, ii and 12 are made to use such a small amount of current that the current cannot energize sufliciently the solenoids 51, 86, etc. and thus prematurely start the condensing units. The time lag'between closing of contacts 62, 65 and 66 can be varied by changing the motor speed of motor 69 by changing the relative :cam positions on shaft 64 or by changing the gears at I0.

If desired, the shunting ofthe program starter when standby current is to be used can be governed by coil 84 in lieu of, or in addition to the control at 88. This is accomplished by providing the contacts 88a which are closed upon energization of coil 84 when the plug 80 is inserted in While we have referred to the receptacle 8|. current from the battery 45 as low voltage'f current, we have used this term for convenience in designation, and it is to be understood that actually this current may be equal to or even in excess of the voltage of the other currents.

The starter contact armatures of starter contacts 14 and 9| are interlocked mechanically, as

on car i3. Each additional car thus equipped may be independently plugged in to standby receptacles. The cars remaining unplugged may remain under control of the program starter.

The operation is as follows:

Refrigeration systems powered from train generator-system Assuming that all refrigerating systems are idle.

it is first necessary to start the blower motors IS- on each car i3, i4, etc. by closing the switch 53 on each car. Assuming also that two or more thermostats on cars I3, l4, etc. closesimultaneously, a slight current flows (in each car) through 51, 56, 58, 59, 60, 43, and Gland respectively through wires 50 and SI, solenoids 61 and II to battery 45. This closes contacts 68 and 68a, either of which starts motor 69. The cam shaft 64 turns and sequentially closes contacts 62, and it If 62 is first closed, coil 61 is shunted out of its corresponding control circontinue to be operated from train current and I cult and a larger current can now flow through starter coil 51, closing contacts "I4 and 'I3.of car I3. This connects motors 26 and 28 with power lines I0a and starts the condensing unit. In the meantime, crank 64 continues to rotate, because contacts 60a are kept closed by current flowing from car I4 through coil II and motor 69 is energized when crank shaft 64 closes contacts 65, the condensing unit motors on car I4 are started in the same manner as described with respect to car I3. As contacts 08a are opened as soon as this occurs, the motor 69 stops.

Whenever a condensing unit (or more than one condensing unit) stops, and its thermostat again attempts to start it, the program starter operates first as previously described, thus preventing the accidental simultaneous starting of two condensing units.

One or more refrigeration systems powered by standby current When one or more plugs 80 are inserted in the standby receptacles, the corresponding condensing unit (or units) is disconnected from the train line I0a by the energization of coil 84 and consequent changing of switch 56 to contact 56. The starter contacts are now under control of the thermostat 43 or other control devices 58, 59 and 55, as well as under control of the phase rotation control 9011.

Operation during cold weather When cold weather is encountered, the switch I00 is placed on contact IOI. If desired, a switch I 00' may be placed on the refrigeration system and interlocked with switch I00 so that I00 is open when switch I00 is on IN. This causes thermostat 42 to control the steam to coil I8 by means of valve 32 and heat the car to the desired temperature.

' Operation in cool damp weather opens and the heating coil is turned 011, permitting the refrigerating system to operatealone.

While the form of embodiment of the'present invention as herein disclosed constitutes a preierred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. An air conditioning system including a plurality of condensing units, a plurality of air condition stats affected by refrigeration pr duced by said condensing units, a program control device including a plurality of sequentially closing contacts corresponding to each of said condensing units and controlling said units, a single wire extending from each of said stats to said program control device and control circuit wiring completing a sequential starting control between said stats, device and condensing units.

2. An air conditioning system including a plurality of condensing units, a plurality of air condition stats afiected by refrigeration produced by said condensing units, a program control device including a plurality of sequentially closing contacts corresponding to each of said condensing units and controlling said units, a motor actuating said contacts, a single wire extending from each of said stats to said program control device and control circuit wiring completing a sequential starting control between said stats, device and condensing units.

3. An air conditioning system including a plurality of condensing units, a plurality of air condition stats affected by refrigeration produced by said condensing units, a program control device including a plurality of sequentially closing contacts corresponding to each of said condensing units and controlling said units, a motor actuating said contacts, asingle wire extending from each of said stats to said, program control device, means automatically starting said motor when one of said stats closes and stopping said motor after the corresponding contact has closed when condensing units and controlling said units, control circuits for each of said condensing units, each circuit including a starting device, a stat, a single wire between said stat and program start device and control circuit wiring completing a sequential starting control between said stats, device and condensing units, said single wire being connected to each of said stats.

'5. An air conditioning system including a plurality of condensing. units, a power line of limited current capacity, starting devices between said line and said condensing units, an air condition stat foreach of said condensing units, a program start device having a plurality of sequentially closing contacts corresponding to each of said condensing units and controlling said units, control circuits for each of said condensing units, each circuit including a starting device, a stat, a single wire between said stat and program start'device, said program start device including a motor sequentially closing said contacts, and means starting said motor when one of said stats is closed and stopping said motor after its corresponding contact has closed when all other of said stats are open and control circuit wiring completing a sequential starting controlbetween said stats, device and condensing units, said single wire being connected to each of said stats.

6. An air conditioning system including a first power line of relatively limited capacity, a second power line of relatively large capacity, a plurality of condensingunits, a program control device, automatic controls for said condensing units, said program control device limiting the number of units which can start simultaneously, means placing said program control device in between said condensing units and said automatic controls when connected to said first power line and for shunting said program control when connected to said second power line.

7. An air conditioning system including a first power line of relatively limited capacity, a second power line of relatively large capacity, a plurality of condensing units, a program control device, automatic controls for said condensing units, said program control device limiting the number of units which can start simultaneously, means placing said program control device in between said condensing units and said automatic controls when connected to said first power line, a phase rotation protector, a plug for connection to said second power line, said protector preventing connection between said plug and condensing units when the phase rotation of said second power line is different from that of said condensing units.

8. An air conditioning system including a power line having generating means of relatively limited capacity, control lines including a control power lead separate from said power line, means energizing said control power lead when said generating means attains a predetermined capacity, a condensing unit, starter means for connecting and disconnecting said condensing unit to said power line, an automatic control for said starter means and including a control circuit between said control power lead and one of said control lines.

9. A train including a plurality of cars, generating means on one of said cars, power lines from said generating means to said other cars; a program start device on one of said cars, a single control wire for each car extending from said program start device to its corresponding car, a low voltage circuit lead extending from a low voltage source to said car low voltage connections to said program start device, condensing units on some of said cars, starters connecting said condensing units and power lines, automatic controls intermittently actuating said starters, and a connection from said low voltage lead to each of said automatic starters and to the respective single control wire, said program start device limiting the number of units which can start simultaneously.

10. A train including a plurality of cars, generating means on one of said cars, power lines from said generating means to said other cars, a program start device on one of said cars, a single control wire for each car extending from said program start device to its corresponding car, a low voltage circuit lead extending from a low voltage source to said cars, low voltage connections to said program start device, condensing units on some of said cars, starters connecting said condensing units and power lines, automatic controls intermittently actuating said starters, evaporating units connected to said condensing units, blowers and blower motors for said condensing units, manual switches'connecting said blower motors and power lines, relays in circuit with said blower motors, and a connection from said low voltage lead to each of said automatic starters and to the respective relay and respective single wire, said program start device limiting the number of units which can start simultaneously.

. DONALD F. ALEXANDER GEORGE C. PEARCE. 

